This invention relates to a crop harvesting header including a sickle knife where the angle of the knife guards relative to the ground can be adjusted for different crop conditions.
Crop harvesting headers, of the type with which the present invention is concerned, generally comprise a header frame structure arranged for movement in a direction of working movement across ground carrying a crop to be harvested; a cutter arranged across a forward edge of the header frame structure for cutting the crop; and a cut crop transport arrangement mounted on the header frame structure for receiving and transporting the cut crop for further processing. The cutter includes a cutter bar defining a flange projecting forwardly from the header frame structure and extending across the header frame structure with a plurality of knife guards mounted on the cutter bar at spaced positions thereon so as to project forwardly therefrom. The conventional sickle knife has a knife drive bar extending across the knife guards for reciprocating movement thereon and a plurality of knife blades carried on the knife bar for co-operation with the knife guards in a sickle cutting action. Each knife guard has at least one guard carrier lug for attachment to the flange by a bolt passing through a hole in the lug and a corresponding hole in the flange with a head on one end of the bolt and a nut on the other end of the bolt for clamping the lug to the flange.
On crop harvesting headers of this type, it is often desirable to have the ability to change the knife guard angle to suit the crop and ground condition.
For example, in some cases it is desirable to run the knife guard at a steep angle relative to the ground in order to have the tip of the knife guards of the sickle very close to the ground. This is desirable when wanting to cut a crop very close to ground (e.g. edible beans).
In other cases, it is desirable to run the knife guard at a flat angle relative to the ground to reduce damage to the knife caused by rocks and to reduce the tendency to scoop up rocks or other foreign material.
The conventional way of changing the knife guard angle has been to change the angle of the whole header platform by means of an adjustable center link. This link can be either mechanical (such as a turnbuckle screw adjustment) or a hydraulic cylinder. Typically an angle change of about 6 degrees is achievable by this method. It would be desirable to provide a substantially larger angle change to meet the requirements described above.
It is one object of the present invention to provide an improved header in which the angle of the knife guards to the ground can be adjusted.
According to a first aspect of the invention there is provided a crop harvesting header comprising:
a header frame structure arranged for movement in a direction of working movement across ground carrying a crop to be harvested;
a cutter arranged across a forward edge of the header frame structure for cutting the crop;
a cut crop transport arrangement mounted on the header frame structure for receiving and transporting the cut crop for further processing;
the cutter including a cutter bar defining a flange projecting forwardly from the header frame structure and extending across the header frame structure;
a plurality of knife guards mounted on the cutter bar at spaced positions thereon so as to project forwardly therefrom;
a sickle knife having a knife drive bar extending across the knife guards for reciprocating movement thereon and a plurality of knife blades carried on the knife bar for co-operation with the knife guards in a sickle cutting action;
each knife guard having at least one guard carrier lug for attachment to the flange by a bolt passing through a hole in the lug and a corresponding hole in the flange with a head on one end of the bolt and a nut on the other end of the bolt for clamping the lug to the flange;
and an arrangement for adjusting an angle of forward projection of the knife guards relative to the flange so as to change an angle of the knife guards relative to the ground comprising:
a first spacer element located between the lug and the flange and a second spacer element located on the bolt;
the first spacer element being shaped such that it is tapered at a set angle so that the first spacer element is thicker on the front side of the bolt and thinner on the rear side of the bolt;
the second spacer element being shaped such that it is tapered at the same set angle so that the second spacer element is thicker on the rear side of the bolt and thinner on the front side of the bolt;
the spacer elements being clamped on the bolt with the flange and the lug to hold the lug at a first angle relative to the flange determined by the set angle;
the first and second elements being arranged such that they can be reversed in position relative to the flange and the bolt so that the first spacer element is thicker on the rear side of the bolt and thinner on the front side of the bolt and the second spacer element is thicker on the front side of the bolt and thinner on the rear side of the bolt to hold the lug at a second angle relative to the flange determined by the set angle and different from the first angle by an angle twice the set angle.
Preferably the spacer elements are arranged such that the bolt is arranged at the set angle relative to a line at right angles to the flange and the head of the bolt has a face parallel to the lug.
Preferably the lug is underneath the flange and the head of the bolt butts the lug.
Preferably one of the spacer elements is on top of the flange and the other is underneath the flange.
Preferably at least one of the spacer elements comprises an elongate bar having a plurality of holes at spaced positions along the bar and each hole arranged for cooperation with a respective bolt. This is advantageous in that it allows the bar to remain held in place by other knife guards when the knife guards are replaced one at a time or individually if damaged. However other arrangements can be used, in particular individual shims for each guard or for each lug.
Preferably each guard has two lugs at spaced positions longitudinally of the flange and wherein at least one of the spacer elements comprises an elongate bar having a plurality of pairs of holes at spaced positions along the bar and each pair arranged for co-operation with a respective guard.
Preferably each of the spacer elements comprises a bar and wherein the first and second spacer elements are of the same length.
Preferably there is provided a hold-down member for engaging the knife, the hold-down member having at least one hold-down member carrier lug attached to the flange by the bolt, the guard carrier lug being located underneath the flange, the first spacer element being located between the guard carrier lug and the flange and the second spacer element being located between the flange and the hold-down carrier lug.
According to a second aspect of the invention there is provided a method for changing the effective cutter bar angle on a crop harvesting header comprising:
providing a crop harvesting header including:
a header frame structure arranged for movement in a direction of working movement across ground carrying a crop to be harvested;
a cutter arranged across a forward edge of the header frame structure for cutting the crop;
a cut crop transport arrangement mounted on the header frame structure for receiving and transporting the cut crop for further processing;
the cutter including a cutter bar defining a flange projecting forwardly from the header frame structure and extending across the header frame structure;
a plurality of knife guards mounted on the cutter bar at spaced positions thereon so as to project forwardly therefrom;
a sickle knife having a knife drive bar extending across the knife guards for reciprocating movement thereon and a plurality of knife blades carried on the knife bar for co-operation with the knife guards in a sickle cutting action;
each knife guard having at least one guard carrier lug for attachment to the flange by a bolt passing through a hole in the lug and a corresponding hole in the flange with a head on one end of the bolt and a nut on the other end of the bolt for clamping the lug to the flange;
the method comprising adjusting an angle of forward projection of the knife guards relative to the flange so as to change an angle of the knife guards relative to the ground by:
providing a first spacer element located between the lug and the flange and a second spacer element located on the bolt;
the first spacer element being shaped such that it is tapered at a set angle so that the first spacer element is thicker on the front side of the bolt and thinner on the rear side of the bolt;
the second spacer element being shaped such that it is tapered at the same set angle so that the second spacer element is thicker on the rear side of the bolt and thinner on the front side of the bolt;
the spacer elements being clamped on the bolt with the flange and the lug to hold the lug at a first angle relative to the flange determined by the set angle;
and reversing in position the first and second elements relative to the flange and the bolt so that the first spacer element is thicker on the rear side of the bolt and thinner on the front side of the bolt and the second spacer element is thicker on the front side of the bolt and thinner on the rear side of the bolt to hold the lug at a second angle relative to the flange determined by the set angle and different from the first angle by an angle twice the set angle.
The invention as defined above therefore provides a means of changing the guard angle on a header. This is done by repositioning tapered shims on both sides of the guard carrier. The shims can be reversed while remaining in the same relative location or can be switched since they are identical and merely opposite their operation.
By having the tapered shims on both sides of the guard bar, the contact surfaces for the head of the bolt and for the nut remain parallel to the face of the fastener.
The change in angle is equal to twice the angle of the shim that is repositioned. For example, if the shim angle is 5 degrees the change in knife guard angle is 10 degrees.
Preferably the shims would consist of an extricable material such as aluminium and cut into lengths such that several knife guards are securing each shim. In this manner, the shim remains secured when the knife guards are replaced.